The Ground Water. 
19 
ably takes place in this case, but the conditions of equilibrium be¬ 
tween the salt solution and the soil are changed, perhaps are con¬ 
stantly changing, and the soil retains more of the sodic chlorid as 
the water table falls, or gives it up as it rises, sometimes in a most 
irregular fashion. Evaporation from the surface and capillarity 
undoubtedly influence these changes continuously. This view 
seems so fully conformable to what we know concerning the deport¬ 
ment of mixed salt solutions when in contact with soil that one is 
tempted to assert it as a demonstrated fact. 
§ 58. Two experiments were made in the hope of gaining 
definite data relating to it. An excavation was made and a sam¬ 
ple taken as soon as the water table was entered, a second sample 
was taken one foot below this, the water from the first foot being 
cut off as completely as possible so that the second sample repre¬ 
sented water from the soil one foot below the water table ; a third 
sample was taken at a depth of an additional foot with the same 
precautions. The respective samples showed the presence of 
0.23286, 0.1771 and 0.1171 parts per thousand. Thirteen days 
later we repeated this experiment, choosing another portion of the 
plot for our observations. The sample of water taken at the sur¬ 
face of the water table contained 0.2129 parts, and the second one, 
taken a foot below the surface, showed the presence of 0.1457 parts 
per thousand. Two other samples were taken at greater depths, 
but the inflow of water .was so great that the results were not so 
reliable. They showed, however, essentially the same as the sec¬ 
ond sample. 
§ 59. The ratios of the chlorin to the total solids in the two 
experiments are not concordant and permit no inference whatever 
to be drawn from them. These facts establish what I have else¬ 
where stated, that the order of solubility of the different salts and 
the laws of diffusion are greatly modified by the properties of the 
soil particles and the relative masses of the soil water and the soil. 
§ 60. The effect of irrigation, particularly when sufficient to 
raise the height of the water table, was to increase the absolute 
quantity of chlorin in the water, but not proportionately with the 
other salts. There were differences in the wells in this respect. The 
ratio of the chlorin to the total solids in well D before irrigation 
was 1:34, and after irrigation 1:64; in wells A and B the changes 
were in the same direction, but much less; in the case of well C the 
change in the ratio, though small, was in the opposite direction. 
The local conditions, including variations in the soil, seem to influ¬ 
ence the amounts of the salts taken into solution and especially the 
relative quantities of the same. The soil in the vicinity of well C 
contained, according to analysis, more than twice as much chlorin 
